1. Field of the Invention
This invention pertains to a method and apparatus for processing citrus products, and more particularly, it relates to a method and apparatus for processing whole citrus fruit to obtain a juice concentrate and dried peel and pulp.
2. Background of the Invention
A citrus processing system commonly in use is shown in FIG. 1 of the drawings, wherein it is indicated as old art. A juice extractor receives the citrus fruit and separates the juice from the residual wet peel and pulp. Further pulp is removed from the juice in a finisher, and the juice is conducted to an evaporator wherein it is evaporated to provide a juice concentrate. A boiler is shown providing a source of steam directed to the juice evaporator so that the required heat for evaporation is provided and juice concentration occurs. A mixer and press is disposed to receive the wet peel and pulp from which a press liquor is obtained as well as a press cake. The press cake is introduced into a dryer, and hot air from a heater is brought into contact with the press cake within the dryer to thereby drive the moisture from the press cake and provide a dry pulp output. Most of the mixture of air and water vapor obtained as the hot air contacts the press cake is directed from the dryer back to the heater where it is mixed with more heated air and noncondensible combustion gases for recirculation to the dryer. A portion of the air and water vapor from the dryer is directed to a waste heat evaporator which receives the press liquor. Evaporation in the waste heat evaporator provides a concentrate of molasses as output. A continuous flow of the air, water vapor and combustion gas mixture is thus directed to the waste heat evaporator, where it is exhausted after a portion of the heat is removed therefrom. Considerable latent heat is lost which is carried in the uncondensed water vapor in the exhaust emanating from the waste heat evaporator in the old art system of FIG. 1. Moreover, the temperature in the dryer of the old art system must be kept below a predetermined maximum so that oxidation of the pulp being dried therein will not occur in the presence of the air and vapor drying blast.
Steam has been used as the drying agent in previous drying systems in general. An example of such a system is seen in U.S. Pat. No. 1,917,841, issued to Hughes et al, wherein a liquid is shown to be dehydrated in a two-step process. Liquid to be concentrated is admitted to a concentrating evaporator to which steam is also admitted for the purpose of partially concentrating the liquid. The partially concentrated liquid is thereafter delivered to a superheated steam dehydrator where it is placed in contact with superheated steam from a superheater. Most of the steam exhausted from the dehydrator with reduced superheat, together with the steam vaporized from the liquid being concentrated, is delivered by conduits back to the superheater. A portion of the exhausted steam is diverted to the concentrating evaporator to provide the heat for this step of the process. Consequently, the liquid is dehydrated in two distinct steps, and the surplus steam obtained from the second step is used to remove some of the moisture from the liquid in the first step. Recirculation of all but the diverted portion of steam back to the dehydrator is accomplished through the superheater for the steam.